1. Field of the Invention
The present invention relates to an observation unit and a microscope system equipped with the observation unit.
2. Description of the Related Art
An optical microscope was originally an optical device that is used by an observer to observe a sample (i.e. an optical image of a sample) with his/her eye(s). Later, a still camera or a movie camera was appended to some optical microscopes to meet user's demand for recording the appearance of samples (their colors and shapes etc.).
When using an optical microscope, an observer observes a sample with his/her eyes through a binocular barrel (or observation barrel). The binocular barrel houses imaging lens systems and prisms, and eyepieces are attached to it.
Some binocular barrels are equipped with a mechanism for shifting the positions of the eye points horizontally and/or vertically to adjust it to the position of the observer during observation and a mechanism for adjusting the angle (elevation angle) at which the observer looks into the eyepieces (Japanese Patent Application Laid-open Publication Nos. H8-278448 and H11-072708).
Some binocular barrels used for instructional purposes allow a plurality of persons (2 to 10 or more) to observe the same sample. This type of barrel is called a discussion barrel (Japanese Patent Application Laid-open Publication No. H10-213752).
On the other hand, with remarkable improvement in the performance, electronic image pickup elements and image display apparatuses in these times have resolving power and gradation equivalent to human eyes in observing samples. Therefore, in some cases an image of a sample is displayed on an image display device or a monitor to allow an observer(s) to observe the displayed image of the sample instead of observing an image with his/her eyes. Some microscopes used in the above-described way of observation do not have a binocular barrel (Japanese Patent Application Laid-open Publication No. 2006-162765).